Transmission device comprising an eccentric power transmission axle that is disposed on the bearing axle

ABSTRACT

There is described in particular a planetary gear which as is normal has a sun wheel ( 1 ), a ring gear ( 2 ) and at least one planet wheel ( 3 ). According to the invention, the planet wheel ( 3 ) is mounted rotatably on a bearing axle ( 10 ), which is provided with a power transmission axle ( 12 ) which is disposed eccentrically relative to the central axle ( 14 ) of the planet wheel ( 3 ) and is intended for power input or power output. The same arrangement is in addition described for a gear device which, instead of the sun wheel and ring gear ( 1, 2 ), has two parallel linear paths ( 38, 39 ).

CROSS-REFERENCE TO A RELATED APPLICATION

The invention described and claimed hereinbelow is also described inGerman Patent Application DE 102 24 999.7 filed on May 31, 2002. ThisGerman Patent Application, whose subject matter is incorporated here byreference, provides the basis for a claim of priority of invention under35 U.S.C. 119(a)–(d).

BACKGROUND OF THE INVENTION

The invention relates to a gear device.

Gear devices of this type are generally configured as planetary gears(for example Johannes Looman “Principles, Constructions, Applications inVehicles”, 3^(rd) edition, volume 26). In their simplest constructionalform, planetary gears of this type have a first path in the form of theexternal circumference of a sun wheel, a second path in the form of theinternal casing of a ring gear which surrounds the sun wheel and atleast one planet wheel which is disposed between these paths and mountedrotatably on a planet carrier (web). The planet wheel is in operationalconnection at its circumference both with the sun wheel and with thering gear, by which there should be understood here for example ameshing (toothed gearing) or a rolling assembly (friction gear).

The actuation or power take-off in planetary gears of this type iseffected for example in that either in the case of a securely-retainedsun wheel, the ring gear is driven, or in the case of asecurely-retained ring gear, the sun wheel is driven and the rotationalmovement which is consequently transmitted by the planet wheel to theplanet carrier is used. Conversely however, also the planet carrier canbe driven and the consequently produced rotational movement can betransmitted to the sun wheel or ring gear.

The power transmission in the region of the carrier is effected,independently of whether the latter is used as actuation or powertake-off element of the gear, via the bearing axle which is situated inthe centre of the planet wheel, about which the planet wheel is mountedrotatably on the carrier. Bearing axle and power transmission axle hencecoincide.

Deviating therefrom, it is known in the case of crank gears, to disposea sun wheel and a planet wheel which is in operational connection withthe latter on a crank disc, and to provide the planet wheel with a powertransmission axle which is disposed eccentrically relative to itsbearing axle and is coupled to the one end of a connecting rod (PCT-WO88/08095). In practice, a serious problem resides thereby in the factthat the power transmission axle does not follow a circular orbitbecause of the inherent rotation of the planet wheel effected duringrotation about the sun wheel, but instead a complicated generallycycloid-type trajectory. This trajectory can indeed be approximated toan elliptical path by optimisation of the sun and planet wheeldiameters. However, achievement of a circular orbit which is desired perse is not possible in the case of gears of this type. It would beequally impossible to achieve for example a linear movement path of thepower transmission axle in the case where the paths which are disposedon both sides of the planet wheel concern linear paths.

In the case of gears of this type, a circular orbit for the powertransmission axle has therefore only been able to be achieved to datewhen the latter coincides with the bearing axle of the planet wheel,which coincides simultaneously also with the rotational axle of theplanet wheel. This has the result that a force exerted upon the powertransmission axle is apportioned respectively half to the operationalconnection between the sun wheel and the planet wheel and to theoperational connection between the planet wheel and the ring gear andthus only half can be transmitted to the sun wheel or ring gear andhence be made useful. In addition, the path which is transmitted to thering gear during a revolution of the planet wheel about the central axleof the planetary gear is always twice as large as the path which thebearing-or power transmission axle of the planet wheel thereby describesabout the central axle of the planetary gear. Therefore, during powerinput or power output at the bearing axle, the result is halving of theforces with doubling of the path covered or vice versa. In other words,of a force exerted upon the power transmission axle, only half istransmitted to the ring gear, which thereby covers twice the path of thepower transmitting axle.

These conditions are unalterable with the construction of planetarygears and comparable gears. Numerous inconveniences for practicalapplication arise therefrom, in particular also with respect to thetransmissible rotational moments and the possible transmission ratios.

SUMMARY OF THE INVENTION

In contrast, the technical problem of the present invention resides inconfiguring the gear device of the initially described type such that itcan be dimensioned more flexibly than previously, the power transmissioncan be improved and nevertheless, according to requirements, a circularor linear path for the power transmission axle can be achieved.

In accordance with the present invention, a gear device is proposedcontaining two parallel paths (16, 17; 38, 39), of which one is disposedin a stationary manner and the other is mounted moveably, at least oneplanet wheel (9, 40) which is disposed between the two paths (16, 17;38, 39, 56), is in operational connection at its circumference with thetwo paths (16, 17; 38, 39, 56) and has a rotational axle (14, 45), abearing axle (10, 30, 44) which is moveable parallel to the two paths(16, 17; 38, 39, 56) and coaxial with the rotational axle (14, 45),about which bearing axle the planet wheel (9, 40) is mounted rotatably,and a power transmission axle (12, 46) which is disposed eccentricallyon the bearing axle (10, 30, 44), the arrangement being such that theplanet wheel (9, 40) can transmit, by means of rolling on the path whichis disposed in a stationary manner, both movements of the powertransmission axle (12, 46) to the moveably mounted path and converselymovements of the moveable path (17, 39, 56) to the power transmissionaxle (12, 46), characterised in that the power transmission axle (12,46) is disposed with such a fixed prescribed spacing from the rotationalaxle (14, 45) that preselected power transmission ratios are produced.

The invention confers the advantage that the power transmission axle canalways be guided on a path upon which also the planet carrier is moved,despite its eccentric arrangement upon the bearing axle. In addition,favourable power transmission ratios are produced since the powertransmission axle can be disposed, according to requirements, muchnearer than previously to the moving path or to the stationary path. Thenew gear device thereby makes possible many constructions which were notpreviously achievable and the use of smaller or larger planet wheels andring gears with otherwise identical ratios.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail subsequently in conjunctionwith the attached drawings of embodiments in which there are shown:

FIG. 1 a schematic representation of a normal planetary gear withstationary sun wheel;

FIG. 2 a schematic representation of a gear device according to theinvention in the form of a planetary gear with stationary sun wheel;

FIG. 3 a schematic cross-section through the planetary gear according toFIG. 2;

FIG. 4 a bearing axle of the planetary gear according to FIGS. 2 and 3with a schematically indicated, radially displaceable power transmissionaxle;

FIGS. 5 and 6 schematic front views of actuation possibilities for theplanetary gear according to the invention;

FIGS. 7 and 8 schematic embodiments of bearing axles of the planetarygear according to the invention;

FIG. 9 to 11 in a schematic comparison, the front views respectively ofa known planetary gear and one according to the invention and of a knowncrank gear;

FIG. 12 a schematic front view of a gear device according to theinvention in linear arrangement; and

FIGS. 13 and 14 schematic front views of two further embodiments of agear device according to the invention in linear arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to FIG. 1, a normal gear device in the form of a planetarygear contains a sun wheel 1, a ring gear 2 and at least one planet wheel3. The sun wheel 1 is configured here in a stationary manner whilst thering gear 2 is mounted rotatably about a central axle 4 of the planetarygear. The sun wheel 1 is provided for example with an external toothingwhich forms a first path which is essentially circular and stationaryhere whilst the ring gear 2 is provided for example with an internaltoothing which forms a second path which is essentially circular andmounted here in a moveable manner, which path is disposed coaxiallyrelative to the first path and surrounds the latter with a pre-selectedspacing. Between the two paths, the planet wheel 3 is disposed such thatit is in operational connection with the two paths essentially atpositions which are diametrically oppositely-situated, in that it isprovided for example with an external toothing which meshes with thetoothings of the two paths of the sun wheel 1 or ring gear 2.

The planetary gear has furthermore a bearing axle 5 per planet wheel 3,which axle is only schematically represented, is mounted on a planetcarrier or web 6 and disposed at a spacing parallel to the central axle4. The bearing axle 5 or the bearing connected thereto serve for therotatable mounting of the planet wheel 3. The planet carrier 6expediently supports the bearing axle 5 on both sides of the planetwheel 3 by arms 6 a, 6 b which are mounted rotatably about the centralaxle 4, at least one arm (for example 6 b) being able to be made torevolve by a drive shaft 7. This has the result that the planet wheel 3rolls on the external path of the stationary sun wheel 1 andconsequently entrains the ring gear 2 on its internal path and sets itin rotational movement about the central axle 4. Therefore a bearingaxle 5 which generally has a small diameter is at the same time a powertransmission axle which converts the circular movement of the carrier 6or the force acting upon the bearing axle 5 of the planet wheel 3 into acorresponding rotational movement of the ring gear 2. In addition, thecentral axle of the planet wheel 3, which is coaxial with the bearingaxle 5, is at the same time the rotational axle 8 thereof, about which arotational movement is implemented during the circling of the sun wheel1.

In the described arrangement, the ring gear 2 is moved, during acomplete revolution of the bearing or power transmission axle 5 aboutthe central axle 4, along a stretch which corresponds to twice thelength of the circle upon which the bearing axle 5 rotates about thecentral axle 4. Independently of the wheel diameters,?·d_(S)+?·d_(H)=2·?d₅ is thereby always valid, in which d_(S), d_(H) andd₅ are the diameters of the sun wheel 1, of the ring gear 2 and of thecircle upon which the bearing axle 5 moves. In addition, of the forcesacting on the bearing axle 5, only half are transmitted to the ring gear2, the ring gear 2 covering twice the stretch compared to the bearingaxle 5, because the power transmission or bearing axle 5 lies preciselycentrally between those two points at which the planet wheel 3 is inoperational connection with the sun wheel or ring gear 1, 2.

Corresponding ratios are produced if the ring gear 2 is stationary andinstead the sun wheel 1 is driven or, if by reversal of the power flow,a rotational movement of the sun wheel 2 or of the ring gear 2 isconverted into a rotational movement of the planet carrier 6 or of theshaft 7 which is coupled to the latter.

In the case of the planetary gear according to the invention representedin FIGS. 2 and 3, the sun wheel 1 and the ring gear 2 are configured asin FIG. 1. The external circumference also of at least one planet wheel9 corresponds to the planet wheel 3 in FIG. 1. The planetary gearaccording to FIGS. 2 and 3 differs however from the planetary gearaccording to FIG. 1 by two essential features. A first distinguishingfeature resides in the fact that the planet carrier 6 has one bearingaxle 10 per planet wheel 9 respectively, which axle is representedhatched in FIG. 2 and the external diameter of which is only slightlysmaller than the external diameter of the planet wheel 9 and thereby ispreferably larger than corresponds to half of the external diameter ofthe planet wheel 9. The planet wheel 9 is thereby configured as a ringand is rotatably mounted on the bearing axle 10 for example by means ofa bearing 11 which can be configured as a ball-, needle- or rollerbearing or the like. A second distinguishing feature resides in the factthat a power transmission axle 12, which is disposed parallel to thecentral axle 4 and is disposed eccentrically relative to a central axle14 (cf. also FIG. 2) of the planet wheel 3, serves for power input orpower output. This central axle 14 corresponds to the central axle 8 inFIG. 1 and is at the same time the rotational axle, about which theplanet wheel 9 can rotate on the bearing axle 10. According to FIG. 2,the power transmission axle 12 is connected to the drive shaft 7 (FIG.2) for example via a lever arm 15 or the like. In the case of the geardevice according to the invention, the carrier 6 which is rotatableabout the central axle 4 of the planetary gear serves hence merely forreceiving or mounting the bearing axle 10, whereas the powertransmission axle 12 serves as actuation or power take-off member, viawhich powers can be input or output.

In FIG. 3, the external circumference of the sun wheel 1, which forms afirst path 16, is indicated schematically by a circle and the internalcircumference of the ring gear 2, which forms a second path 17, isindicated by a further circle. Both paths 16, 17 are disposed coaxiallyat a spacing which corresponds to the diameter of the planet wheel 9,which is in operational connection at a position 18 with the path 16 andat a position 19 with the path 17 by means of tooth meshing, frictionalengagement or the like. If therefore the bearing axle 10 is made torevolve by means of the lever arm 15 (cf. also FIG. 2) which is fittedon the power transmission axle 12, then the planet wheel 9 in fact rollson the fixed path 16 in the case of a stationary sun wheel 1 as in FIG.1, whilst it simultaneously sets the ring gear 2 in a rotationalmovement by means of the operational connection at the position 19. Anessential difference from FIG. 1 however resides thereby in the factthat the power transmission axle 12 is disposed with a pre-selectedspacing from the rotational axle 14 of the planet wheel 3 and is mountedon the bearing axle 10.

The power transmission axle 12 can technically be produced for exampleby means of the central axle of a pin which protrudes perpendicularlyfrom the bearing axle 10. According to a particularly preferredembodiment of the invention, this pin, as indicated in FIG. 4, ismounted on the bearing axle 10 displaceably along a diameter, so thatthe power transmission axle 12 can be disposed according to requirementsmore or less far from the rotational axle 14 of the planet wheel 3 andcan be brought into a multiplicity of possible positions (for example 12a, 12 b, 12 c or 12 d). For this purpose, a pin which produces forexample the power transmission axle 12 is disposed displaceably in adiametrically extending groove of the bearing axle 10 and in a fixedmanner by a locking screw or the like.

A particular advantage of the planetary gear according to the inventionresides in the fact that the power transmission axle 12, independentlyof where it has been disposed on the bearing axle 10, always describes,during operation of the planetary gear, a circular path 20 about thecentral axle 4, which circular path is represented in broken lines inFIG. 3. It is therefore readily possible, despite its eccentricarrangement, to drive it in the same manner as in FIG. 1. This isrepresented for example in FIGS. 5 and 6. In FIG. 5, the powertransmission axle 12 is produced as a pin 21 which is connected to apiston 24, which is guided in a cylinder 23, via a connecting rod 22. Ifthe piston 24 is moved to and fro in the direction of a double arrow v,then as a result the pin 21 or the power transmission axle is guidedupon the circular orbit 20 with the result that the movements describedwith reference to FIG. 1 are possible. If this concerns a planetary gearwith a stationary sun wheel 1, then for example the ring gear 2 is setin a circulatory rotational movement. This rotational movement can betransmitted to a further wheel 25 of the planetary gear which rolls onthe external circumference of the ring gear 2. If conversely the wheel25 by necessity is driven, this movement can be converted into a to andfro movement of the piston 24. Furthermore, with the wheel 25, any perse arbitrary gearing up or gearing down or rpm change in comparison tothe rpm of the ring gear 2 can be brought about.

In the embodiment according to FIG. 6, for example two planet wheels 9,which are diametrically oppositely-situated, are mounted rotatablyrespectively on bearing axles 10 of identical construction on the planetcarrier 6. In this example, each bearing axle 10 has a powertransmission axle which is produced by a pin 26, which powertransmission axle has the same spacing relative to the rotational axle14 of the respective planet wheel 9. The actuation or power take-off ofthe planetary gear is effected here in that both pins 26, which aremoveable on the circular orbit 20, are connected to each other by meansof a connection rod 27, which is mounted on a shaft 28 which correspondsto the shaft 7 in FIG. 1 and is coaxial with the central axle 4 of theplanetary gear. The shaft 28 can, according to the case, serve asactuation or power take-off shaft. Furthermore, the device according toFIG. 6 corresponds to that of FIG. 5. Alternatively, the two pins 26 canalso have different radial spacings from the central axle 4. Inaddition, the actuation or power take-off can be effected analogously bymeans of a connecting rod which acts on one of the pins 26.

FIGS. 7 and 8 show two alternative embodiments for the constructionalconfiguration of the bearing axle 10, which is configured in FIG. 2 to 6as a cylindrical disc. As FIG. 7 shows, the cylindrical disc can bereplaced by a component which is configured for example as a flat bar29. As a result, a bar-shaped bearing axle 30 is obtained, which isprovided at its ends with individual bearing elements 31 in the form ofbearing balls, rollers or the like, on which a cylindrical internalcasing 32 of the annular planet wheel 9 can roll. Simultaneously, thebearing axle 30 can be connected to the carrier 6 by means of anextension 29 a of the flat bar 29. On the other hand, in the case of theembodiment according to FIG. 8, a corresponding bar-shaped bearing axle30 serves as carrier of the internal ring of a normal ball bearing 33,on the external ring of which the internal casing 32 of the planet wheel9 is mounted. Furthermore, the arrangement according to FIG. 8corresponds to that of FIG. 7. In both cases, the power transmissionaxle 12 is produced by means of a pin 34 which is coaxial thereto and isdisposed eccentrically relative to the central or rotational axle 14 ofthe planet wheel 9.

FIG. 9 to 11 show the functions which are important for the invention ofa normal planetary gear (FIG. 9), of a planetary gear (FIG. 10)according to the invention and of a normal crank drive (FIG. 11). It isthereby a prerequisite in all three cases that the power transmissionaxle 5, 12 or 35 (FIG. 11) has the same spacing a from the central axle4 of the gear and an additional actuation or power take-off wheel 36,which is configured analogously to FIG. 5 and FIG. 6, has the samediameter. In addition, for the sake of simplicity, it is assumed for theposition of the power transmission axle 12 or 35 that this has thegreatest possible spacing from the central axle 4 and hence, in FIGS. 10and 11, also has the greatest possible eccentricity.

For the known planetary gear according to FIG. 9, the dimensioning ofthe sun wheel 1 and of the ring gear 2 is chosen such that atransmission ratio of 1:4 is produced for the wheel 36. For a staticstate, which is taken by way of example and obvious from FIG. 9, it istrue in addition that a force F1 which acts on the externalcircumference of the ring gear 2 at the position 19 according to FIG. 3(operational engagement between ring gear 2 and planet wheel 3) must bemaintained in equilibrium by means of a force F2 which iscounter-directed, acts on the power transmission axle 5 and is twice asbig as the force F1 with F2=2·F1.

In the embodiment according to the invention according to FIG. 10, onlya force F3=F1 is required on the other hand in the case of the identicalspacing a in order to compensate for a corresponding force F1. Inaddition, here both the diameter of the ring gear 2 and the diameters ofthe planet wheels 3 can be considerably reduced. The ensuingtransmission ratio is 1:3 for the wheel 36. Because F1=F3, also therespective paths are the same instead of twice as big as in FIG. 9.

In the case of a gear device according to FIG. 11 configured as a crankdrive, in which a crank disc 37 is mounted rotatably on a centralbearing 38 and is provided at the circumference with the powertransmission axle 35, a transmission ratio of 1:2 is produced in thecase of identical power transmission as in FIG. 10.

An essential advantage of the planetary gear according to the invention,which is produced directly from FIGS. 9 to 11, resides in the fact thatby moving the power transmission axle 12 in the direction of FIG. 4 withotherwise identical dimensions, completely different power transmissionratios can be produced. Instead of the previous non-variable powerdistribution of 1/2 to 1/2 at the positions 18, 19 in FIG. 9, in thecase of the gear according to the invention, any other distributions areprovided, which lead to correspondingly different diameters of thecircular orbit 20 (FIG. 3), upon which the power transmission axle 12moves. Theoretically, the power distribution can be varied in the caseof the gear according to the invention between 1:0 and 0:1, according towhether the power transmission axle 12 is positioned at the position 18or at the position 19. In the case of a particularly advantageousvariant, the arrangement is therefore such that the power transmissionaxle 12 can be displaced, even with an operating planetary gear, betweenthe two possible extreme positions according to requirements. Anarrangement of the power transmission axle 12 in the vicinity of the sunwheel could thereby be advantageous for producing braking forces in thecase of a fixed sun wheel 1 or for improving the power transmission inthe case of a stationary ring gear 2. In a similar fashion, by means ofenlargement of the sun wheel 1 and simultaneous reduction of the planetwheel 9, an rpm change can be produced which would, in the case of thesmallest conceivable planet wheel, be approximately 1:4. In addition tothe advantage that the power transmission axle 12 is always moved upon acircular orbit (for example 20), independently of its position on thebearing axle 10, the advantage of high flexibility is hence alsoproduced with the choice of the different gear parts since, differingfrom previous practice, it is not two pre-selected gears which determineall other gear parts. Apart from that, it is clear that the powertransmission axle 12 can be placed respectively only as far on theexternal circumference of the bearing axle 10 as is possible onpractical grounds.

The operating principle of the gear device according to the inventiondescribed with reference to FIG. 2 to 11 can in an analogous manner alsobe applied to gears with linear paths instead of circular orbits. Thisis described subsequently by way of example with reference to FIG. 12 to14.

FIG. 12 shows a first, linear path 38, disposed in a stationary manner,which can be conceived of as a development of the external circumferenceof the sun wheel 1 or of the path 16 according to FIG. 3. Situatedparallel, opposite and at a spacing thereto, is a second, likewiselinear, movably mounted path 39, which can be conceived of as adevelopment of the internal circumference of the ring gear 3 or of thepath 17 according to FIG. 3. A planet wheel 40 is disposed between thetwo paths 38, 39, the circumference of which is in operationalconnection on the one hand at a position 41 with the stationary path 38and on the other hand at a position 42, which is diametricallyoppositely-situated, with the moveable path 39. The planet wheel 40 isconfigured as a narrow ring analogously to FIG. 2 to 11, which ring ismounted rotatably on a bearing axle 44 by means of a bearing 43, theexternal circumference of which bearing axle is preferably only slightlysmaller than corresponds to the external diameter of the planet wheel40. A central axle 45 of the bearing axle 44 is simultaneously therotational axle of the planet wheel 40. The bearing axle 44 can bemounted on a carrier which is mounted displaceably parallel to the paths38, 39 and is not represented in more detail.

Analogously to FIG. 2 to 11, the bearing axle 44 is provided in additionwith a power transmission axle 46 which is disposed eccentricallyrelative to the central or rotational axle 45 of the planet wheel 40,which power transmission axle is produced for example as a pin, whichprotrudes perpendicularly from the bearing axle 44 which is configuredas a circular disc. Finally, a guide element 47 serves for actuation orpower take-off, which guide element is displaceable parallel to thepaths 38, 39, is coupled to the power transmission axle 46 or to the pinand is displaceably mounted in the corresponding bearings 48. The linearmovement which is introduced by the guide element 47 can be convertedinto a rotational movement by means of a wheel 49 which is inoperational connection with the external side of the moveable path 39,and conversely the rotational movement of the wheel 49 can also beconverted into a linear movement of the guide element 47. With respectto the power transmission and the paths to be covered, the sameprinciples apply as have been explained above with reference to FIG. 1to 11. In particular, the guide element 47 is configured and guided bymeans of the bearings 48 such that on the one hand it can only be movedparallel to the paths 38, 39, on the other hand the power transmissionis effected from the guide element 47 to the bearing axle 44 or,conversely, in the region of the power transmission axle 46, or theforce direction parallel to the paths 38, 39 extends through the powertransmission axle 46. Hence the guide element 47 and the bearing axle 44can also be produced in one piece without configuring a bearing pin. Inorder that no undesired lever effects are obtained between the guideelement 47 and the bearing axle 44 or the bearing pin 46, the centralaxle thereof is expediently precisely upon a line 47 a, which isindicated in broken lines and along which the guide element 47 acts onthe balls or the like of the bearings 48 or vice versa.

The embodiment according to FIG. 13 corresponds essentially to theembodiment according to FIG. 12, as a result of which the same parts areprovided with the same reference numbers. Additionally to FIG. 12,bearings 50 for guidance of the moving path 39 are representedschematically. In addition, a cable winch 51, mounted in a stationarymanner, is represented schematically, which cable winch corresponds tothe wheel 49 in FIG. 12 and is in operational connection with the movingpath 39. The cable winch 51 contains a winding body 52 for a cable 53,which can be wound up by means of displacement of the guide element 47onto the winding body 52 or can be unwound from the latter. At the cableend, there is situated a load 54, by means of which it is intended to beindicated that the gear device according to the invention according toFIG. 13 can be used for example in the manner of a hoist for liftingloads.

The embodiment according to FIG. 14 corresponds essentially to theembodiment according to FIG. 13, as a result of which the same parts areprovided with the same reference numbers. Differing from FIG. 13, amoveable path 56 is configured as the straight strand of an endlesselement 57 in the form of a chain, a cable or a belt. The element 57 isguided in a circulating manner upon two deflection wheels 58, 59 (chainwheels or pulleys). One of these deflection wheels is configured as acable winch analogously to FIG. 13 and is provided with the winding body52 for the cable 53. The planet wheel 40 is provided with an externaltoothing for the case where the element 57 is a chain, which toothingengages directly in the chain strand which is in operational connectiontherewith, whilst the path 38 in this case is a toothed rack. If theelement 57 comprises a belt, the planet wheel 40 is configured as afriction roller or the like and the path 38 is configured as a rollingpath.

The invention is not restricted to the described embodiments which canbe modified in many ways. This is true in particular for thedimensionings and relative arrangements of the various parts to eachother which are indicated by way of example. The planetary gear can forexample also be equipped with more than one or two planet wheels.Furthermore, the bearing axle can be configured differently than isindicated in FIGS. 3, 7 and 8. In particular, it is possible toconfigure the bearing axle in a multipart manner. It can thereby beparticularly expedient to provide it with two coaxial parts which aresituated axially one behind the other and are connected to each other bymeans of a spring element. Hence forces which impact upon one of theparts can be cushioned, before they act upon the other part. In additionit can be advantageous to configure the ring gear 2 on the externalcircumference as actuation or power take-off element, in that it isprovided for example with a circumferential toothing or the like.Alternatively however, the actuation or power take-off element can alsocomprise a plurality of wheels which are disposed coaxially one behindthe other and provided with different diameters, in particular toothedwheels, in order to make different transmission ratios possible in asimple manner. The planet carrier 6 can also be configured, instead ofas a circular disc as is indicated in FIG. 3, also as a lever arm or insome other way. Furthermore, it is clear that the paths 38, 39 in FIG.12 to 14 need not be configured exactly straight, but can extend alsoalong an arc. The paths 38, 39 can thereby comprise for example toothedracks, chains, rolling faces or the like, which are in operationalconnection with the planet wheels 40 in the form of toothed- orfrictional wheels. Furthermore, it is clear that the power transmissionratios can be improved further in that a crank 54 with a crank arm 55which is disposed parallel to the power transmission axle 12 is attachedto the power transmission axle 12, as is indicated in FIG. 3. Finally itshould be understood that the different features can be applied also incombinations other than those described and represented.

1. Gear device, containing: two parallel paths (16, 17; 38, 39), ofwhich one is disposed in a stationary manner and the other is mountedmoveably, at least one planet wheel (9, 40) which is disposed betweenthe two paths (16, 17; 38, 39, 56), is in operational connection at itscircumference with the two paths (16, 17; 38, 39, 56) and has arotational axle (14, 45), a bearing axle (10, 30, 44) which is moveableparallel to the two paths (16, 17; 38, 39, 56) and coaxial with therotational axle (14, 45), about which bearing axle the planet wheel (9,40) is mounted rotatably, and a power transmission axle (12, 46) whichis disposed eccentrically on the bearing axle (10, 30, 44), thearrangement being such that the planet wheel (9, 40) can transmit, bymeans of rolling on the path which is disposed in a stationary manner,both movements of the power transmission axle (12, 46) to the moveablymounted path and conversely movements of the moveable path (17, 39, 56)to the power transmission axle (12, 46), characterised in that the powertransmission axle (12, 46) is disposed with such a fixed prescribedspacing from the rotational axle (14, 45) that preselected powertransmission ratios are produced.
 2. Gear device according to claim 1,characterised in that the bearing axle (10, 30, 44) has a diameter whichis between 0.5 times and 1 times the value of the diameter of the planetwheel (9, 40), and in that the planet wheel (9, 40) is configured as aring which is mounted rotatably on the bearing axle (10, 30, 44). 3.Gear device according to claim 1, characterised in that the spacing ofthe power transmission axle (12, 46) from the rotational axle (14, 45)can be altered.
 4. Gear device according to claim 1, characterised inthat it is configured as a planetary gear.
 5. Gear device according toclaim 4, characterised in that the path (16) which is disposed in astationary manner is formed by the external circumference of a sun wheel(1) and the moveably mounted path (17) is formed by the internalcircumference of a ring gear (2) of the planetary gear.
 6. Gear deviceaccording to claim 5, characterised in that the path (17) which isdisposed in a stationary manner is formed by the internal circumferenceof a ring gear (2) and the moveably mounted path (16) is formed by theexternal circumference of a sun wheel (1) of the planetary gear.
 7. Geardevice according to claim 4, characterised in that the bearing axle (10)is mounted on a planet carrier (6) which is mounted rotatably about thecentral axle (4) of the planetary gear.
 8. Gear device according toclaim 4, characterised in that the power transmission axle (12) isconfigured as a pin (26) which protrudes from the bearing axle (10) andis coupled to a connection lever (27), which is positioned on a driveshaft (28) which is mounted rotatably about the central axle (4) of theplanetary gear.
 9. Gear device according to claim 4, characterised inthat the power transmission axle is configured as a pin (21) whichprotrudes from the bearing axle (10) and is coupled to a connecting rod(22) of a crank drive.
 10. Gear device according to claim 4,characterised in that the ring gear (2) is configured on the externalcircumference as actuation or power take-off element.
 11. Gear deviceaccording to claim 10, characterised in that the actuation or powertake-off element has a plurality of actuation or power take-off wheelswhich are disposed coaxially one behind the other and provided withdifferent diameters.
 12. Gear device according to claim 10,characterised in that it contains at least one rotatable wheel (25)which is in operational connection with the actuation or power take-offelement.
 13. Gear device according to claim 1, characterised in thatboth paths (38, 39, 56) have a linear or arcuate configuration.
 14. Geardevice according to claim 13, characterised in that it contains abar-shaped guide element (47) which is mounted displaceably parallel tothe paths (38, 39, 56) and is coupled to the bearing axle (44) in theregion of the power transmission axle (46).
 15. Gear device according toclaim 13, characterised in that the guide element (47) is mounted inbearings (48) in order to avoid undesired lever effects between it andthe power transmission axle (46), the lines of action (47 a) of whichbearings are essentially in the same plane as the power transmissionaxle (46).
 16. Gear device according to claim 13, characterised in thatit contains at least one rotatable actuation or power take-off wheel(49, 51) which is in operational connection with a side of the moveablepath (39) which is orientated away from the planet wheel (40).
 17. Geardevice according to claim 13, characterised in that the paths (38, 39,56) are configured as toothed racks, chains, cables or rolling faces.18. Gear device according to claim 1, characterised in that the bearingaxle (10, 30, 44) comprises at least two parts which are coupled bymeans of a spring.